1. Field of the Invention
The present invention generally relates to an image management device and an image management method, and more particularly to an image management device and an image management method, both managing taken images radiographed as medical images and processed images created from the taken images.
2. Related Background Art
Conventionally, in a medical field, various modalities such as an X-ray radiographing device, a computer tomography (CT) device, a magnetic resonance imaging (MRI) device and a computed radiography (CR), which use radiations such as an X-ray, are used for a diagnosis.
These digital images are stored in a format in conformity with a standard generally called as digital imaging and communication in medicine (DICOM). The format is configured as a hierarchical structure. A layer of test is located at the uppermost hierarchy. A layer of series is located under the test, and a layer of image is located under the series.
Because these layers are considered based on radiographing, the test is located at the uppermost layer. Consequently, when DICOM images are searched from a database (DB) to be displayed as a list, the list of test, which is located at the uppermost layer, is generally displayed.
Moreover, each digital image is classified into classes by its modality. For example, a CT image is classified into a CT class, and a CR image is classified into a CR class. To put it more concretely, for example in the case of the CT class, ID indicating the CT class is recorded at an image header.
On the other hand, a new digital image can be created by performing image processing of a digital image. Such a newly created image is classified into a class called as a secondary capture (SC).
On the other hand, in X-ray radiographing aiming at a medical diagnosis, a film screen system combining an intensifying screen with an X-ray radiographing film has been used. In a radiographing method using the system, X-rays having passed a subject include the internal information of the subject, and the X-rays are converted into visible light in proportion to the intensities of the X-rays. Then, the X-ray radiographing film is exposed by the visible light, and an X-ray image is formed on the film.
Conventionally, when a diagnosis is performed with such a film, in order to judge the progress of a disease and the progress of curing, the diagnosis has been performed by arranging two images radiographed with an interval with time on a Schaukasten or the like to compare both the images.
On the other hand, in the field of orthopedic surgery or the like, in order to radiograph a big subject which is too large to be radiographed by one-shot, a plurality of times of X-ray radiographing is performed, and a diagnosis and a measurement are performed by joining a plurality of the radiographed films to one another.
For example, it is necessary for a diagnosis of scoliosis to radiograph the overall view of the backbone, and there is a case where the subject is larger than the size of a radiographing device to make it impossible to radiograph the subject by one-shot. In such a case, the radiographing is performed over two times, and the created two sheets of X-ray films are physically glued together with an adhesive tape or the like for the judgment of symptoms.
On the other hand, an X-ray digital radiographing device has been begun to be used recently which composes a digital image by reading a radiation image as an electric signal by various systems and converting the electric signal into a digital signal, which systems are a system of reading an X-ray intensity distribution after forming the X-ray intensity distribution as a latent image of energy in a stimulable phosphor, a system of reading the fluorescence distribution of phosphor by X-rays directly, a system of not using any fluorescence distribution, and the like.
Thereby, because the radiographed image can be taken in as digital data, it has become possible to acquire a difference between pieces of digital data acquired with a time interval by image processing. Consequently, the progressing situation or the curing situation of a disease is conventionally judged by a human head by comparing two images arranged on a Schaukasten or the like with each other.
In recent years, as described above, because it has become possible to perform X-ray digital radiographing to acquire image data as digital data, by displaying a difference image acquired by operating the difference between two X-ray images on a monitor or the like as a reference image, the clear proceeding of curing or the progressing of a disease is shown by referring to the difference image by the digital image processing without judging changes of the progressing situation or the curing situation of an affected area by the comparison with a past image as described above. Consequently, the presentation of a difference image is very effective means for supporting the judgment of a doctor.
On the other hand, also in the field of the orthopedic surgery, similarly it has become possible to handle image data as digital data. Consequently, although two images have been joined to each other by gluing them physically with an adhesive tape or the like until now, it has become possible to perform a diagnosis by joining two images to each other more easily and more accurately by digital image processing. Consequently, a subject measured by gluing two films physically in the prior art has become possible to be measured in a moment on a monitor, and then the X-ray digital radiographing has become effective means for decreasing the workloads of a doctor.
Here, there is a method of storing the history of image processing as prior art of the method of displaying images processed in the past (for example, Japanese Patent Application Laid-Open No. 2003-284691).
Moreover, there is also a method of creating incidental information including the information indicating the storage place of image data (for example, Japanese Patent Application Laid-Open No. 2003-196300).
Moreover, a compression/registration combining technique for implementing a time subtraction as an application service provider for detecting variations of medical imaging with time is also disclosed (for example, Japanese Patent Application Laid-Open No. 2003-126046 (corresponding to United States Patent Published Application No. 2003-35584)).
Furthermore, also an image display device enabling an easy search and the like by making each image be accompanied by history information such as the information on whether an operation between images has been performed or not, and the information for specifying the images used as the basis of the operation between the images when the operation between the images has been performed is disclosed (for example, Japanese Patent Application Laid-Open No. 2001-218110 (corresponding to United States Patent Published Application No. 2001-10732)).